Equalization of the D.C. null in high density digital magnetic recording

The DC null in a digital magnetic recording channel is equalized in a novel way which allows recovery of "write" current waveforms with no modulation coding constraints. The technique involves use of simple non-linearities coupled with a pulse slimming filter, integrator and limiter. Performance is analyzed for Lorentzian signals in the presence of media dominant noise. Theoretical performance capabilities are compared with differentiator-based systems. The technique described eliminates the need for automatic gain control.